Over half a century ago Francis Crick and James D. Watson proposed the double helix model for the DNA molecule, believing they had, as Crick put it, "found the secret of life." Discoveries of recent decades, however, have only raised more questions about the true nature of life. Here the French biology professor who gave us The Misunderstood Gene surveys our various definitions of life since ancient Greece. Then, with clear logic and intriguing details of advances in molecular genetics, evolutionary biology, and astrobiology, he establishes life's essential characteristics. The road to an understanding of life remains incompletely charted, Michel Morange concludes, but the nature of its final destination is no longer an enigma.

"I won't give away Morange's thoughtful and persuasive payoff, but his demand that children undergo compulsory education in philosophy of science is energizing."—Guardian (London)

"After addressing definitions of life proposed by others, Morange outlines 'three essential characteristics' of life: reproductive ability, complex molecular structures and the metabolic replication of those structures. From there, Morange discusses a range of current inquiries, among them astrobiology research, genome studies and adaptation in extreme conditions. An informative and engaging tour of life, and our understanding of it, as a process 'perpetually being transformed'."—Publishers Weekly